package 成绩;

import java.util.Scanner;

class Kao{
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        System.out.println("成绩：");
        int temp=scanner.nextInt();
        if (temp>=80 && temp<=100){
            System.out.println("A");
        }else if (temp>=70 && temp<80) {
            System.out.println("B");
        }else if (temp>=60&&temp<70){
            System.out.println("C");
        }else {
            System.out.println("D");
        }
    }
}